Muscle Dynamic Imaging & Spectroscopy
Thursday 23 April 2009
Room 312 13:30-15:30

Moderators:

 Chris Boesch and Michael D. Noseworthy
 
13:30 679. Quantification of Dynamic In Vivo 3-D Muscle Moment Arms Using Cine-PC MRI
    Nicole A. Wilson1, Abrahm J. Behnam1, Frances T. Sheehan1
1Rehabilitation Medicine, National Institutes of Health, Bethesda, MD, USA
   

This is the first study to characterize the relative moments of the individual quadriceps components in vivo during dynamic volitional activity using phase contrast MR imaging. Accurate values of musculotendon moment arms are essential for modeling applications, determination of musculotendon material properties, and the study of pathology. Current results serve as a basis for exploration of how pathologies, such as patellofemoral pain, effect and are affected by the moment arms and relative moments of the knee joint. The methodologies developed advance the use of phase contrast MRI for full 3-D tracking of bone, tendon, and muscule during a single experiment.
     
13:42 680. Prediction from Finite Element Modeling of Non-Uniform, Region-Dependent Strain of Muscle Fibers During Passive and Eccentric Rotation of the Ankle Confirmed by Phase Contrast MRI
    David Dongsuk Shin1, John A. Hodgson2, Sheng-Wei Chi3, Jiun-Shyan Chen3, V Reggie Edgerton2, Shantanu Sinha4
1Biomedical Engieering, University of California, Los Angeles, CA, USA; 2Physiological Science, University of California, Los Angeles, CA, USA; 3Civil & Environmental Engineering, University of California, Los Angeles, CA, USA; 4Radiology, University of California, San Diego, CA, USA
    PC-MRI was used to estimate muscle fiber deformations in the medial gastrocnemius muscle undergoing passive and eccentric length changes. There was a progressive change in strain along fibers and along the proximo-distal axis of the muscle. Proximal fibers strained most near their origin and distal fibers strained most near their insertion. These data confirm predictions from FEM indicating that fibers will strain most in high stress regions of the muscle. The finding is contrary to the widely held view that muscle fibers strain uniformly along their length and suggests that intramuscular structural materials play an important role in force transmission.
     
13:54 681. DTI Based Muscle Fiber Tractography in Humans at 4 Tesla Using Stimulated-Echos
    R. Allen Waggoner1, Toshiaki Oda2, Ryuta Kinugasa2,3, Kenichi Ueno4, Kang Cheng1,4, Hideo Yokota2, Ryutaro Himeno2
1Laboratory for Cognitive Brain Mapping, RIKEN - Brain Science Institute, Wako-shi, Saitama-ken, Japan; 2Living Matter Simulation Research Team, RIKEN, Wako-shi, Saitama-ken, Japan; 3School of Sport Sciences, Waseda University, Tokorozawa, Saitama-ken, Japan; 4fMRI Support Unit, RIKEN - Brain Science Institute, Wako-shi, Saitama-ken, Japan
    Due to the extremely short T2 of muscle, DTI studies of muscle have to date been limited to 3T and lower. The use of the Stimulated-Echo for studying diffusion in systems with short T2 and long T1, has a long history. With the application of two different Stimulated-Echo based pulse sequences, we were able to perform DTI based tractography of human calf muscle at 4 Tesla and resolve dense fiber tract bundles.
     
14:06 682. Reproducibility of Diffusion Tensor Imaging in Human Forearm Muscles
    Martijn Froeling1, Jos Oudeman2, Sandra van den Berg2, Klaas Nicolay1, Mario Maas2, Gustav Strijkers1, Maarten Drost3, Aart Nederveen2
1Biomedical NMR, Department of Biomedical Engeneering, Eindhoven University of Technology, Eindhoven, Netherlands; 2Department of Radiology, Academic Medical Center, Amsterdam, Netherlands; 3Department of Human Movement Sciences, Maastricht University, Eindhoven, Netherlands
    In this study we investigated the reproducibility of DTI applied to the human forearm muscles. We used a fast clinical protocol and investigated the reproducibility of DTI parameters. We have shown that DTI of the human forearm is possible and that the derived parameters are reproducible within a certain range.
     
14:18 683. Proton MRS Acquisition Scheme with Long Echo Time and Without Water Suppression Simplifying IMCL Evaluation
    Jimin Ren1,2, A. Dean Sherry1,3, Craig R. Malloy1,4
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA; 2Department of Radiology, University of Texas Southwestern Medical Center; 3Department of Chemistry, University of Texas at Dallas, Richardson, TX, USA; 4VA North Texas Health Care System
    Proton MRS enables resolution of intra- from extra-myocellular lipids (IMCL and EMCL) in skeletal muscle. However, in a conventional muscle proton MR spectrum acquired at short echo time (TE) is often featured with severe overlapping EMCL and IMCL signal, which requires fitting procedures to separate these two components, even for spectra collected on ultra-high field scanner at 7 Tesla. This post-processing, unfortunately, is cumbersome. The current study evaluated a long TE scheme without water suppression for soleus and gastrocnemius muscles of 20 healthy human subjects, all with significantly improved chemical shift resolution. The mechanism of resultion enhancement was also discussed.
     
14:30 684. Optimal IMCL/EMCL Peak Separation and Full Visibility of the Dipolar Coupled Cr CH3 Resonance in Human Tibialis Anterior Muscle at 7T
    Hermien E. Kan1, Maarten J. Versluis1, Mark A. van Buchem1, Andrew G. Webb1
1Radiology, Leiden University Medical Center, Leiden, Netherlands
    In 1H MRS of skeletal muscle, signals for intra myocellular lipids (IMCL) and creatine can be poorly visible due to peak overlap dependent on the angle of the muscle fiber with respect to the external magnetic field. This results in challenges in the reliable determination of absolute concentrations of these compounds from the same voxel. In this work we show that at a field strength of 7T in the tibialis anterior muscle, both compounds are very well visible and quantifiable due to the increased spectral resolution.
     
14:42 685. Kinetics of Muscle Lactate and High Energy Phosphates Measured by Localised Quantitative Interleaved MRS During Recovery from Ischaemic Exercise Define the Contributions of Lactate Oxidation, Lactate Efflux and Other Processes of Acid Efflux
    Graham Kemp1, Martin Meyerspeer2,3, Ewald Moser2,4
1Magnetic Resonance and Image Analysis Research Centre, University of Liverpool, Liverpool, Merseyside, UK; 2MR Centre of Excellence, Medical University of Vienna, Vienna, Austria; 3Center for Biomedical Engineering and Physics, Medical University of Vienna, Vienna, Austria; 4Department of Radiology, Medical University of Vienna, Vienna, Austria
    31P MRS offers insight into skeletal muscle bioenergetics, but can only measure some of what is of interest. A quantitative 1H MRS method for muscle lactate interleaved with 31P MRS permits fuller quantification of the processes responsible for production and buffering of metabolic acid. In recovery from ischaemic exercise (n=5) we used lactate, pH and PCr measurements to quantify the processes responsible for clearing the acid load to permit recovery of pH. We conclude that oxidation can be only a minor contribution, the majority of lactate being exported, this being however, only a small contribution to overall acid clearance.
     
14:54 686. Metabolic Adaptations of Creatine Deficiency in Skeletal Muscle
    Christine Nabuurs1, Martijn Romeijn1, Andor Veltien1, Hermien Kan1, Dirk Isbrandt2, Arend Heerschap1
1Radiology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands; 2Center for molecular neurobiology, Institute for signal transmission, Hamburg, Germany
    Defects in the biosynthesis of Cr are known to have major effects on brain function and can be successfully treated by Cr supplementation. However, effects of Cr on muscle metabolism have not been fully elucidated yet. In this study, in vivo 31P MRS was applied to yield responses of PCr and Pi levels to Cr supplementation and ischemic conditions in knockout mice with a defect in Cr biosynthesis. The results indicate an upregulation of ATPase at very low PCr concentrations and changes in the PCr¡êATP¡êPi equilibrium during treatment and restriction of Cr.
     
15:06 687. DTI-Based Fiber Tracking Reveals a Multifaceted Alteration of Pennation Angle and Fiber Tract Length Upon Muscle Lengthening
    Anneriet M. Heemskerk1, Bruce M. Damon1
1Vanderbilt University Institute of Imaging Science, Nashville, TN, USA
    DTI-based muscle fiber tracking enables 3D reconstruction of an entire muscle’s architecture, which is not possible with any other technique. The purpose of this study was to analyze the 3D changes in pennation angle (è) and fiber tract length (Lft) upon muscle lengthening and determine if these changes are heterogeneous. Each of six subjects was imaged with his/her foot in three positions. Upon muscle lengthening, è decreased and Lft increased, with è showing a heterogeneous pattern along the aponeurosis. This study offers exciting possibilities for better understanding of structure-function relationships in muscle.
     
15:18 688. Appearance of Histopathologic Changes of Rotator Cuff Tendons in MRI
    Florian M. Buck1, Holger Grehn2, Bernhard Jost2, Monika Hilbe3, Silvana Manzanell4, Juerg Hodler1
1Department of Radiology, Balgrist University Hospital, Zurich, Switzerland; 2Orthopedic Surgery, Balgrist University Hospital, Zurich, Switzerland; 3Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland; 4MSRU, Equine Hospital, Vetsuisse Faculty, University of Zurich, Zurich, ZH, Switzerland
    Problem: MR signal alterations of the rotator cuff tendons are incompletely understood. Method: MR signal of cadaveric rotator cuff tendons was compared to histological changes. Results: Compared to normal tendon, mucoid degeneration is hyperintense in T2w fs and PDw fs sequences. For the evaluation of the tendon diameter involved, T2w fs sequences were superior to T1w or PDw fs sequences. Chondromatous metaplasia is common in rotator cuff tendons. Compared to normal tendon it is hyperintense in T1w, T2w fs, and PDw fs sequences. Conclusion: Tendon hyperintensity can be caused by a number of different histological abnormalities. Their conspicuity depends on the type of sequence.